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(No Model.) 3 Sheets-Sheet 2.

J. H. BLESSING & O. H. OVERTON.

DUPLEX STEAM ENGINE.

No. 451,904. Patented May 5,1891.

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W. WMML (No Model.) 3 Sheets-S.heet 3.

J. H. BLESSING 8v '0. H. OVERTON DUPLEX STEAM ENGINE.

110. 451,904. Patented May 5, 1891.

Maj/M9585: Irwniors: & $111 J/JAME'S H BLESS/1V6 W CHARLES H OVERTON,

Wmmi UNITED STATES ATENT F F JAMES H. BLESSING AND CHARLES H. OVERTON,OF ALBANY, NEXV YORK; SAID OVERTON ASSIGNOR TO SAID BLESSING.

SPECIFICATION forming part of Letters Patent No. 451,904, dated May 5,1891.

Applic i n filed $eptember 26,1889. Serial No. 325,118. (No model.)

To aZZ whom it may concern.-

Beit known that we, JAMES H. BLESSING and CHARLES H. OVERTON, both ofthe city and county of Albany, in the State of New York, have inventednew and useful Improvements in Duplex Steam-Engines, of which thefollowing is a specification.

Our invention relates to improvements in that class of steam-engines inwhich two independent steam cylinders, each provided with areciprocating piston, are employed to transmit theirpower to a singleshaft; and the object of our invention is to simplify the constructionin such manner that the power derived from both pistons will be applieddirectly to asingle crank, and so that the slidevalves of both engineswill be properly operated by a single eccentric, the parts being soconstructed that the stroke of the pistons will be greater than thethrow of the crank to which they are connected, whereby we are enabledto attainahigher rate of piston speed with a given number of strokesthan can be obtained from an engine of the ordinary constructionhavingthe same length of crank, and the distance traveled by either pistonwhile the engine-shaft is making a complete revolution will approximatethe circumference of the circle described by the center of the crankpinof said engine-shaft. By our construction we are enabled to attain withone crank and crank-shaft the full effect of two engines connected totwo cranks fixed at right angles on the same shaftthat is to say, whenthe piston of either engine has attained its midstroke position thepiston of the opposite engine will be at one of the extreme points ofits stroke, and we are also enabled to operate the valves of both of theengines by means of a single eccentric that is common to the twoengines. 7

We attain our object by the mechanism illustrated in the accompanyingdrawings, which are herein referred to and form part of thisspecification, and in which- Figure 1 is a partial plan view of ourduplex-engine adapted to operate duplex-pumps, the balance-wheel andsteam-chests being removed to expose the slide-valves and theiroperating mechanism, one of the pistons being at the extremity of itsmovement in one direction and the other approaching a like position.Fig. 2 is a like view showing the crank at one of its ordinarydeadcenter points, the two pistons moving in opposite directions. Fig. 3is a transverse section of Fig. 1 at the line X X. Fig. 4; is anenlarged and detached plan View of the triple arm which connects the twopiston-rods with the crank-pin, and Fig. 5' is a skeleton diagramshowing the positions of the triple arm at eight different butequally-spaced points in the circle described by the center of thecrank-pin.

While we have shown in the drawings our invention as applied to ahorizontal form of engine, it should be understood that it is equallyapplicable to any other form of duplex engines.

As represented in the drawings, A designates the steam-cylinders of ourengine,which, for the sake of convenience, will be referred to as theright and left engine, as viewed by a person facing the outer end ofsaid cylinders. The two cylinders may be made in one piece, as in thedrawings, or separately with the usual steam and exhaust ports andpassages, and they are provided with the usual pistons employed inreciprocating engines.

Bis the frame or bed-plate of the engine, which in the form shown in thedrawings also forms the heads for the steam-cylinders A and thepump-cylinders C, but the form of said frame may be changed to suit theparticular style of engine required.

D is a guide-bar which extends to opposite ends of the frame B, and isprovided with parallel sides 1, which form an open guide for partshereinafter described. Said guidebar is also provided with a boss 2,which forms one of the bearings for the crankshaft E, the other bearing3 for said shaft being formed on the frame B. The crank-shaft E isprovided with a crank F, whose crankpin 4 (indicated by dotted lines inthe drawings) receives the motion imparted from both pistons of theengine.

G designates the piston-rods of the engine. The outer end of each ofsaid piston-rods is secured in a cross-head H, to the opposite end ofwhich in the form of engine shown in the drawings a pump-plunger I issecured, said plunger forming a guide, which relieves the piston-rod ofa lateral strain to which it is liable to be subjected. Said cross-headwhen preferred and in other forms of our engines may be provided withany other form of guide. The cross-head H is preferably made with anopening 5, over which at one end lugs 6 extend on the upper and lowersides, and a wrist-pin 7 is fixed in said lugs to form a journal for oneend of a connecting-link J, which is located in the opening 5, so as tobringsaid link on a level with the centerline of the piston-rod, andthereby relieve the latter from the strain which would arise from fixingthe wrist-pin either on the upper or lower side of the cross-head.

K is a triple arm by which power and motion from the pistons of theengine are transmitted to the crank-shaft E. Said triple arm is providedwith an opening 8, which is equidistant from each of its end centers.Two branches of said triple arm range in direct line with each other andthe other branch forming a right angle therewith. The ends of thefirst-named branches are bifurcated to form lugs 9, that extend over andunder the cross-head H, and each pair of said lugs is provided with awrist-pin 10 to receive the end of the correspondinglink J, and therebyeffect the connection of the cross-heads with the triple arm K.

L is a guide-block that is fitted to slide back and forth in the lowerpart of the opening formed in the guide-bar D by the parallel sides 1.Said guide-block is provided witha stud or pivot 11, which fits into theopening Sin the triple arm K and forms a fulcrum on which the latterreceives a vibratory motion by reason of its connection to the crank F,the single arm of the triple arm K being connected to the crank-pin ofsaid crank by a split box 12 or other suitable or analogous means andthe sliding movementof the guide-block L in the guide-bar D permittingthe triple-arm K to follow in a direct line the movement produced by thethrow of said crank.

M designates the slide-valves for governing the admission and exhaustionof steam into and out of the cylinders A. Said valves are secured tovalve-rods 13, which are jointed to the opposite ends of the twodirectbranches of a triple arm N that corresponds essentially to thetriple arm K, but whose single arm is provided with an eccentric strapor hoop let, which is fitted to engage upon an eccentric O, fixed on theshaft E. The triple arm N is provided with a central opening that isfitted to engage on a pivot 15, fixed in a sliding guide-block P, whichmoves in the upper part of the opening formed in the guide-bar D, saidguide-block and pivot forming a shifting fulcrum for the triple arm N,whereby the latter is enabled to follow the movements imparted theretoby the eccentric O.

Q is a balance-wheel that is secured to the shaft E for the purposewhich said wheels are commonly employed on steam-engines.

R is an air-chamber (shown in Fig. 3) that is provided for the pumpsattached to and operated by the engines shown in the drawings. Saidpumps do not form any part of our present invention, and therefore donot require further illustration or description.

The operation of our engines will be understood by the followingdescription, in connection with the diagram shown in Fig. 5: Premisin gthat the valve-operating mechanism is adjusted to run the engines sothat the crankshaft E will revolve in the direction indicated by thecurved arrows in Figs. 2 and 5, and that when the crank-pin is in thepositions 1 and 5 on the line of the path of said crank-pin on thediagram shown in Fig. 5, in which positions the crank F will be, at thetwo extreme points of its throw, in a line parallel to the center lineof the cylinders A; or in the positions commonly known as thedead-centers in engines. of ordinary construction the triple arm K willattain positions where its two direct branches will stand at a rightangle to the center line of the cylinders, and the pistons of the twoengines will be in corresponding positions, the position of said pistonscorresponding to the point 1 on the path of the crank-pin in saiddiagram, being indicated by dotted lines in Fig. 2, equidistant from thecylinder heads nearest the crank shaft. Then the crank-pin has reachedthe point 2 on its path, the piston of the right engine will have movedbackward to its mid-stroke position and the piston of the left enginewill have moved forward to the extreme end of its stroke toward thecrank-shaft,.and it will be seen by reference to said diagram that inmoving to the position last named the piston of the left engine willhave moved a distance equal to the distance between the points 1 and 2'on the lower line of said diagram beyond the termination of its strokein that direction if the engine was connected directly to the crank inthe usual manner. After passing the point 2 and until the point 4 on thepath of the crank-pin is reached the piss tons of both engines will movein the same direction, toward the cylinder-heads farthest from thecrank-shaft. \Vhen the point 4 has been reached, the piston of the rightengine will be at the extreme end of its stroke in the direction lastreferred to, wherein the stroke of said piston will exceed the stroke ofa pis ton connected directly to a crank in the ordinary manner by adistance equal to that between the points 4" and 5" on the upper line ofthe diagram, and the piston of the left en gine will be at itsmid-stroke position. WVhen the crank-pin has reached the point 5 on thepath of said crank-pin, the two pistons will stand opposite each otherinthe end of the cylinders farthest from the crank-shaft; but neither ofsaid pistons will then be at that extrem ity of its stroke. When thecrank-pin has reached the point 6,the piston oftheleft engine will haveattained the extremity of its stroke in the direction farthest from thecrank-shaft, the movement in that direction exceeding the throw of thecrank in the same direction by a distance equal to the distance betweenthe points 5 and 6' on the lower line of the diagram, and the piston ofthe right engine will be at its mid-stroke position. while the crank-pinis passing from the point 6 to 8 the pistons of both engines will movein the same direction, and at the last-named point the piston of theright engine will have attained the extremity of its stroke toward thecrank-shaft, again exceeding the stroke due to the throw of the crankwhen connected directly to the piston, as hereinbefore described, andthe piston of the left engine will again be at its mid-stroke positionand while th e crank-pi n is moving from 8 to l thepiston of the rightengine will move backward and the piston of the left engine will moveforward until both have attained the initial positions hereinabovedescribed, and thereby a complete double stroke'of both pistons will beaccomplished and the parts in position for a repetition of theoperations just described. The triple arm N transmits the motion of thecocentric O to the slide-valves of both engines in such manner that theadmission and exhaustion of steam in both engines will occur at exactlythe right times to produce the operations of the latter above described.

In the drawings the triple arm K is made with all its branches of thesame length from the pivotal center of said arm to the point ofconnection of each branch. By such a construction the pistons will havea stroke that is slightly in excess of the circumference of the circledescribed by the center of the crank pin; but by shortening the branchof said arm that is connected to the crank-pin,mak-

ing the length of said arm about five-sixths of the others, the strokeof the pistons will conform Very closely to the circumference of saidcircle.

Instead of applying the power of the engines for operating pumps in themanner illustrated in the drawings, power may be taken directly from thecrank-shaft in the manner commonly followed in obtaining motion fromsteam-engines, and our engines in an inverted form will have advantagesfor driving screw-propellers for marine purposes.

lVhat we claim as our invention, and desire to secure by Letters Patent,is

In a duplex steam-enginefthe combination of two steam-cylinders, whichare each provided with the usual piston and piston-rod, a shaft providedwith a single crank, and two triple arms, each comprising a continuousbeam having a single arm projecting at right angles therefrom and eachbeing pivoted at the junction of its single arm with its continuous beamto shifting fulcrums, which are fitted to move in guides, one of saidtriple arms being connected at its opposite ends to the piston-rods ofthe engines and its single arm being connected to the single crank of anengins-shaft, and the other triple arm being c011- nected at itsopposite ends to the valve-rods and its single arm being connected toasingle eccentric on the shaft of said engine, as and for the purposeherein specified.

JAMES H. BLESSING. CHARLES H. OVERTON. Witnesses:

WM. I-I. Low, S. B. BREWER;

